The present invention relates to superconducting electronic devices, and more specifically, to high fidelity threshold detection of single microwave photons using a quantum non-demolition photon detector.
In the state-of-the-art, in the optical frequency domain, reliable single photon detectors such as photomultipliers, microwave kinetic inductance detectors, and superconducting nanowire single-photon detectors are widely used in various experiments and applications. However, one disadvantage of these devices is that they destroy (i.e., absorb) the photons that they detect. In contrast, in the microwave domain, i.e., the gigahertz (GHz) range, reliable and practical single photon detectors are still under research and development.